Re: [PATCH v3 3/7] dt-bindings: watchdog: dw-wdt: Add watchdog TOPs array property

[Guenter Roeck <linux@roeck-us.net>]

On Tue, May 26, 2020 at 06:41:19PM +0300, Serge Semin wrote:
> In case if DW Watchdog IP core is built with WDT_USE_FIX_TOP == false,
> a custom timeout periods are used to preset the timer counter. In
> this case that periods should be specified in a new "snps,watchdog-tops"
> property of the DW watchdog dts node.
> 
> Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> Reviewed-by: Rob Herring <robh@kernel.org>
> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: linux-mips@vger.kernel.org

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> 
> Changelog v2:
> - Rearrange SoBs.
> - Move $ref to the root level of the "snps,watchdog-tops" property
>   so does the constraints.
> - Add default TOP values array.
> - Discard the label definition from the new bindings example.
> 
> Changelog v3:
> - Remove items property and move the minItems and maxItems constraints to
>   the root level of the snps,watchdog-tops property.
> ---
>  .../bindings/watchdog/snps,dw-wdt.yaml        | 32 +++++++++++++++++++
>  1 file changed, 32 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/snps,dw-wdt.yaml b/Documentation/devicetree/bindings/watchdog/snps,dw-wdt.yaml
> index 5bf6dc6377f3..d9fc7bb851b1 100644
> --- a/Documentation/devicetree/bindings/watchdog/snps,dw-wdt.yaml
> +++ b/Documentation/devicetree/bindings/watchdog/snps,dw-wdt.yaml
> @@ -39,6 +39,23 @@ properties:
>      description: Phandle to the DW Watchdog reset lane
>      maxItems: 1
>  
> +  snps,watchdog-tops:
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +    description: |
> +      DW APB Watchdog custom timer intervals - Timeout Period ranges (TOPs).
> +      Each TOP is a number loaded into the watchdog counter at the moment of
> +      the timer restart. The counter decrementing happens each tick of the
> +      reference clock. Therefore the TOPs array is equivalent to an array of
> +      the timer expiration intervals supported by the DW APB Watchdog. Note
> +      DW APB Watchdog IP-core might be synthesized with fixed TOP values,
> +      in which case this property is unnecessary with default TOPs utilized.
> +    default: [0x0001000 0x0002000 0x0004000 0x0008000
> +      0x0010000 0x0020000 0x0040000 0x0080000
> +      0x0100000 0x0200000 0x0400000 0x0800000
> +      0x1000000 0x2000000 0x4000000 0x8000000]
> +    minItems: 16
> +    maxItems: 16
> +
>  unevaluatedProperties: false
>  
>  required:
> @@ -55,4 +72,19 @@ examples:
>        clocks = <&per_base_clk>;
>        resets = <&wdt_rst>;
>      };
> +
> +  - |
> +    watchdog@ffd02000 {
> +      compatible = "snps,dw-wdt";
> +      reg = <0xffd02000 0x1000>;
> +      interrupts = <0 171 4>;
> +      clocks = <&per_base_clk>;
> +      clock-names = "tclk";
> +      snps,watchdog-tops = <0x000000FF 0x000001FF 0x000003FF
> +                            0x000007FF 0x0000FFFF 0x0001FFFF
> +                            0x0003FFFF 0x0007FFFF 0x000FFFFF
> +                            0x001FFFFF 0x003FFFFF 0x007FFFFF
> +                            0x00FFFFFF 0x01FFFFFF 0x03FFFFFF
> +                            0x07FFFFFF>;
> +    };
>  ...